blood flow rate measurement by using nano …flexi tube again using the araldite adhesive. we...

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Int. J. Mech. Eng. & Rob. Res. 2014 Aadarsh Mishra, 2014

BLOOD FLOW RATE MEASUREMENT BY USING

NANO-PIEZOELECTRIC SENSOR

Aadarsh Mishra1*

*Corresponding Author: Aadarsh Mishra � [email protected]

This study was to Design a setup used to measure the flow using piezoelectric sensor for medicalpurposes using the property of piezoelectricity. The piezoelectric disc used is shown below. Two/four piezoelectric discs were placed in line, inclined or parallel on a flexi tube (ACLYRIC)and theoutputs observed for various waveforms and levels of water to measure the direction of Fluid.

Keywords: Blood flow rate, nano-piezoelectric, Medical purpose

INTRODUCTION

The main objective of this project was todevelop a blood Flow meter to measure thevelocity and direction of blood flow in veinswhich is crucial information for a doctor duringany surgery. This blood flow meter would usepiezoelectric sensors of the smallest sizeavailable to perform the operation.

PIEZOELECTRICITY

In 1880, Jacques and Pierre Curie discoveredan unusual characteristic of certain materials:when subjected to a mechanical force, thecrystals became electrically polarized. Tensionand compression generated voltages ofopposite polarity, and in proportion to theapplied force. Subsequently, the converse ofthis relationship was confirmed: if one of these

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Vol. 3, No. 3, July 2014

© 2014 IJMERR. All Rights Reserved

Int. J. Mech. Eng. & Rob. Res. 2014

1 Department of Mechanical Engineering, Manipal Institute of Technology, Manipal University, Manipal, Karnataka 576104.

voltage-generating crystalswas exposed to an electricfield it lengthened orshortened according to thepolarity of the field, and inproportion to the strength ofthe field.

These behaviors were labeled thepiezoelectric effect and the inversepiezoelectric effect, respectively, from theGreek word piezein, meaning to press orsqueeze.

It is the property of certain crystallinesubstances to generate electrical charges onthe application of mechanical stress.

Conversely, if the crystal is placed in an electricfield, it will experience a mechanical strain.

Research Paper

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Quartz is a well-known single crystalmaterial depicting such piezoelectric property.

METHODOLOGY

The project is focused on the development ofa blood flow meter. The basic experiment totest the working of piezoelectric sensor usedin the flow meter consists of 2 piezoelectricdiscs. This disc on one end is connected to aresistor (1 Kilo Ohm) which in turn is connectedto a signal generator. A voltmeter is connectedin parallel to the resistor. The otherpiezoelectric disc is connected to anoscilloscope.

Figure 1: Crystal Structure of aPiezoelectric Ceramic

Figure 2: Medical Piezoceramic Discs

Figure 3: Block Diagram of the Setup

PIEZOELECTRIC DISCS

This project consists of a piezoelectric discthat generates electrical charges onapplication of mechanical stress. Converselyif it is placed in an electric field it will experiencemechanical strain. Such elements are usefultransducer elements which transduce electricalenergy into mechanical energy and vice versa.When an AC voltage is applied, it will cause itto vibrate and thus generate mechanical wavesat the same frequency of the input AC field.Similarly, it would sense the input mechanicalvibrations and produce the proportionalcharge at the matching frequency of themechanical input.

They are available in various shapes andsizes. For the experiment performed we used

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the piezoelectric discs shown below. For theactual application we are going to use 3 mmsize piezoelectric sensor of square shapewhich has been ordered and will be deliveredin a couple of weeks.

• Light-weight 2-wire operation (IEPE)

• Ultra low noise

• Wide dynamic range

• Wide temperature range

• Simple signal conditioning

• Cost effective test implementation

Figure 4: Medical Piezoceramic Discs

GENERATOR AND MOTOR

ACTIONS OF PIEZOELECTRIC

ELEMENTS

Why Do We Use Piezoelectric

Sensor?

• Small size

• Broad frequency range

Figure 5: Generator and MotorActions of a Piezoelectric Ceramic

APPLICATIONS

These materials are available in a variety ofshapes and sizes such as disks, plates, bars,rings, rods, tubes, etc.

Some of the typical applications are:

• High Voltage Generators for gas lighters

• Fuses for explosives

• Ultrasonic cleaner

• Ultrasonic welders

• Ultrasonic atomizer’s

• Nebulizers

• Strain and excitation gauges

• Accelerometers

• Flow meters

• NDT transducers

• Dynamic force and pressure measurement

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• SONAR

• Deep water hydrophones

• Piezoelectric actuators/translators

THE DIFFERENT TYPES OF

PIEZO TESTING MODULE

FOR FLOW MEASUREMENT

Setup-1

This setup was made by taking a flexi tube of9 cm length and we cut out two circular portionsof the tube in line with each other with a blade.Take two piezoelectric discs we fit them in thecircular holes and stuck the edges using fevicolquick adhesive and an adhesive called aralditewhich is water resistant. Taking a small squarepiece of aluminum we closed one end of theflexi tube again using the araldite adhesive.

We connected each piezoelectric to achannel of the oscilloscope one at a time afterit was placed firmly in the flexi tube. We tappedthe center of the piezoelectric discs with themaximum force and the waveforms verify thatthe piezoelectric discs were working properly.

Figure 6: Piezo Testing Modulefor Flow Measurement

PROJECT EXECUTION

• Two piezoelectric discs are attached to aflexi tube opposite to each other at the samelevel from ground.

• One piezoelectric disc is connected to a 1Kilo Ohms resistor which in turn isconnected to the signal generator.

• A voltmeter is connected in parallel with theresistor which measures the voltage acrossthe resistor. When this voltage is divided bythe resistance we obtain the current flow inthe circuit.

• The two ends of the piezoelectric disc 1 isalso connected to the channel 1 of theoscilloscope.

• The other piezoelectric disc is connectedto the channel 2 of the oscilloscope whichshows the output.

• Water is filled into the flexi tube.

• The input and output waveforms are noticedsimultaneously on the CRO and the outputvoltage, resistor voltage and hence thecurrent are noted down for differentfrequencies, input voltage and waveforms.

Setup-2

This setup was made by taking a Acrylic Rodof 10cm length, 2cm Diameter. First we drill ahole of diameter 0.8cm And after that we Makea triangular Cut of 1cm Height,0.2cm Base asshown in fig. In those Cut off , we goanna placethe .3cm Diameter Piezeo electric sensorfacing parallel to each other .We will place 4Piezeo out of which 2 will act as a receiverand 2 as a transmitter. All these piezeosignalgoanna intersect at one point which will tell usthe Direction of flow of fluid.

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CONCLUSION AND FUTURE

WORK

We hope to use this piezoelectric disc of 3 mmor smaller size in a blood flow meter where itshall detect the velocity and direction of bloodflow. Also we hope to prepare a compact designto provide the proper signal to the piezoelectricdisc of 1 MHz frequency with options for tuningthe same. On delivery of the requiredpiezoelectric sensors another experiment shallbe conducted in a similar fashion as the realmodel of blood flow meter.

REFERENCES

1. General information on piezoelelectricshttp://sparklerceramics.com/pdf/SP-010-05.pdf

2. PZT http://www.americanpiezo.com/piezo-theory/pzt.html

3. Piezoelectricity http://www.americanpiezo.com/knowledge-center/piezo-theory/piezoelectricity.html

4. Piezo ceramics http://www.ceranova.com/technlgy/piezo.htm

Figure 7: Actual Front View of Setup

Setup-3

This setup was made by taking a Acrylic

Cuboid of Dimension 20cm length And 6cm

.A hole has been drilled through it and having

diameter 1cm and two piezeo is fixed in it , on

both side and for water filling and discharge

two opening are there at top .This setup is

being fabricated at NAL Workshop ,Bangalore

under the guidance of a Ph.D. scholar Ajay

This graph depicts an almost linear rise in

current with increase in level of water. However

it may vary slightly with various trials.

Figure 8: Actual Front View of Setup

blood flow rate measurement by using nano …flexi tube again using the araldite adhesive. we...

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